16. Describe your
personal, professional, or educational experiences or situations that have contributed to your
desire to pursue advanced study in science, mathematics, or engineering.Review the instructions for the Previous
Research Experience Form to avoid duplicating information. Type single-spaced
using 10-point font size or larger. There
is a 1-page limit.

My recent experiences involving science
writing and its connections to my research have substantially contributed to my
desire to continue pursuing a career in theoretical astrophysics.For the past year, I have worked as a staff
writer for the Berkeley Scientific Journal, a bi-annual undergraduate-run
science journal published on campus at UC Berkeley.Thus far, I have written an article for each
of the past two issues, one dealing with quantum
computation and its suggestive support for the many worlds interpretation of
quantum mechanics, and the other focusing on the special importance of the
fundamental constants of physics for life.Writing these articles has represented the culmination of my lifelong
interest in popular science, drawing upon the inspiration I’ve received from
authors like Brian Greene, Lee Smolin, David Deutsch,
James Gleick, Richard Dawkins, and Timothy Ferris, to
name several of those most influential to me.In the future, I hope to continue to publish articles in science
magazines and eventually author popular science books, both of which have
provided a much needed source of inspiration and motivation, along with a big
picture perspective that neither my courses or
research could provide on their own.

Of the authors mentioned above, I have
actually had the chance to meet half of them, via public lectures and various
informal talks on campus here at Berkeley.One such experience that helped to convince me I am on the right track
as a potential theoretical physicist, came after a
talk given by Brian Greene, a Columbia University theoretical physicist and
expert on Superstring theory, a topic on which he authored the recent
best-seller, “The Elegant Universe”.Superstring theory itself postulates that space has extra dimensions that
are tightly curled up at the microscopic level.Having studied the expansion of the space through my research, I’ve
often wondered, if the universe is expanding, “Where does that new space
actually come from?”With this in mind,
after the talk, I approached Brian Greene and asked him if one could think of
the expansion of space as being due to the slow unfolding of these tightly
curled up higher dimensional spaces, and had anyone ever thought of looking
into that before?After pausing for a
moment, he said yes, one could certainly think of it that way, and as far as he
knew, no one had ever conceived of it in those terms.He then told me that it would be cutting edge
research, although it would probably take a lifetime.Hearing that, at the very least, I may have
been the first to think of something like this, and hearing it from one of the
worlds leading experts in the field, is something that can not help but lift
one’s spirits.

Recently, events regarding the second
article that I wrote for the Berkeley Scientific Journal and its connection to
my research have also helped to lift my spirits.As described in more detail in the research
experience essay, for over two years I have been doing research in astrophysics
searching for supernova explosions with Professor Alex Filippenko.We meet regularly on Wednesdays for our
research group meetings and the atmosphere is usually quite informal, as we
traditionally eat pizza, talk about recent observations, and whatever
theoretical astrophysics topics come up.I can not deny that the relaxed and intellectually supportive atmosphere
of the group has significantly influenced my decision to pursue a career in
astrophysics.But in particular, in a
group meeting several weeks ago, with no notice whatsoever, Alex says, “Andy,
why don’t you give us a talk about your article in the Berkeley Scientific
Journal.” which had just been published.Although I had not expected it and therefore had not prepared anything,
I was quite excited about giving an impromptu presentation, and in the end, I
gave quick half-hour talk which led to a group discussion lasting over two
hours.I had previously done a formal
presentation discussing my research at an undergraduate research poster session
run by the Berkeley Society of Physics Students, but this particular experience
was even more rewarding.Whether the
setting is formal or informal, any opportunity to present ideas that interest
you to a genuinely receptive audience is something to be treasured.And from a purely practical standpoint, with
journal talks, colloquia, and, of course, oral exams, similar on the spot
presentations will undoubtedly be crucial in graduate school and beyond.

As it happened, the content of my article
made it particularly relevant to be having this discussion with Alex at that
time.My article discusses the idea of
the “fine tuning” of the fundamental constants of physics, where even tiny
changes in the numerical values of constants like the speed of light and
Newton’s gravitational constant could easily lead to a universe quite
un-hospitable to life.For example,
small tweaking of the parameters could lead to universes without stars or
stable chemical elements, which are undoubtedly crucial prerequisites for life
as we know it.These ideas, and the
question of whether the universe is indeed fine-tuned for the existence of
life, formed the subject matter of a public debate between Alex and Frank Shu, also a Professor of Astronomy at UC Berkeley.The debate was part of an event called “Wonderfest”, a bay area forum where various scientific
experts came to debate important scientific and philosophical issues.Sitting in the audience and watching Alex and
Frank engage in intellectual sparring, I was particularly struck by the fact
that I had inadvertently given Alex a quick review of the subject through my
article and impromptu talk a few weeks earlier.As the whole set of events unfolded, I could not help but thinking that
it may not be so unlikely that, someday, it will be me up there in Alex’s
shoes.It is indeed my desire to be a
scientist like Alex who is relentlessly enthusiastic about debating these types
of philosophical questions in a setting so conducive to the spirit of
discovery.In addition to seeing Alex in
this debate, I have been fortunate to work with him in several contexts, as a
researcher, a student, and as a teaching assistant for an introductory
astronomy course taught by him.There is
no question that Alex has been a mentor for me, and considerably influenced my
desire to continue to pursue a career in astrophysics.

As people continue to ask me why I am
doing astrophysics, I have realized that at the heart of it, the philosophical
implications behind it all are really what drive me.Simply put, I want to understand how the
universe works and contribute to its understanding as much as I can in my
lifetime.How old is the universe?What is driving the expansion of the
universe?What sets the values of the
Fundamental Constants of Physics?These
are the kinds of questions that continue to make this field worthwhile, despite
the large number of overwhelmingly esoteric steps involved in gaining a decent
understanding of our current best answers to these questions.Recently, I have been fortunate to experience
a genuine convergence between my courses, my research, and my efforts at
science writing, which have all related directly towards answering these types
of questions.As a taste of what is
likely to come in graduate school and the rest of my career, this convergence
has solidified my desire to pursue advanced study in theoretical astrophysics
and strengthened my eventual hope of making a significant contribution to my
field.

NSF Question 17

17. Describe your
experiences in the following: Integrating research and education (for example,
participating in and encouraging discovery at various levels); advancing
diversity in science (for example, contributing to the participation of
underrepresented groups); contributing to your community (both scholarly and
social). Type single-spaced using 10-point font size or larger. There is a 1-page limit.

My experiences with science writing and
teaching have allowed me to integrate my research with education and make
contributions to both the scientific community and the general public, in ways
which I hope to continue throughout my career in astrophysics.Such endeavors can also be helpful aids
towards advancing diversity in science, and have been so to some degree in my
previous experience.

As discussed in the previous essay, for
over a year I have worked as a staff writer for the Berkeley Scientific
Journal, (BSJ) where I have written a science article for each of the past two
issues.One major motivation I have for
writing is simply to give back to the community of potential readers,
scientists and non-scientists alike.Well before I became certain I would pursue a career in science, popular
science writings had inspired me to creative thought in ways that few other
reading choices could.And as a
scientist, what these books and articles have done that neither my academic
courses or, until recently, my research has done, is to put the things I am
doing into a well-conceived big picture perspective.In helping us to perform such personal
reflection and place our roles as scientists in the proper context, these
writings fill a genuine need in the scientific community.Scientists who do not step away from
themselves and perform a meta-analysis of what they are doing and why they are
doing it are simply doing themselves and their peers a
disservice.It is in this sense that I
view popular science works as terribly important, not only as means toward
communicating important scientific ideas to the general public, but also as a
sort of glue that holds the scientific community itself together via social and
intellectual common ground.As a
beginning science writer, it is in this spirit that I strive to emulate those
who have so deeply influenced me, and draw upon their inspiration to eventually
make my own impact upon both the scientific community and the community at
large.

In addition to writing for BSJ, I have
also done graphic design work for the journal, designing the journal covers and
selected graphics for both the Spring and Fall 2001 issues.I have found that the careful use of
graphical images can be an extremely useful tool towards communicating
scientific ideas to the general public or even an expert audience.While cover art is often more of a practical
advertisement for the internal content of a science magazine or book, graphics
related to the article itself can be crucial at making the article an effective
means of communication.As an example of
what I have done, in my most recent article, I needed to create a graphic to
help convey the essence of superstring theory, which happens to postulate that
space has at least 6 extra dimensions hidden at the microscopic level.Since a six-dimensional object is inherently
impossible to draw, I decided to produce a schematic illustration designed
purely to convey the complexity of the higher dimensional object.I ended up taking a sufficiently complex
two-dimensional geometrical design I had drawn, wrapping it around a sphere
using graphics programs, and then texturing the surface with bumps and
depressions corresponding to changes in brightness in my initial drawing.What resulted was an unearthly image that
served its purpose quite well. For more details and other BSJ graphics, see http://www.ugastro.berkeley.edu/~friedman/AndysWebPage/BerkeleyScientificJournal.html.By continuing to create graphical aids like
these that help illustrate scientific concepts, I hope to further contribute to
the community of science readers.

In regard to teaching, this semester I
have had the opportunity work as a teaching assistant for Astronomy 10, UC
Berkeley’s introductory Astronomy course taught by Alex Filippenko.Teaching in this setting is excellent
preparation for the inevitable teaching responsibilities I will have in
graduate school, and it will undoubtedly help me become a better lecturer,
wherever I eventually find myself in the academic world.And with Astronomy 10 especially, as an
introductory breadth course, I am learning a great deal about how to
communicate scientific ideas to what amounts to an approximate version of the
general public in a much more personal context than through science writing
alone.I am constantly learning from my
students where I can improve my explanations and teaching style, and with their
help, I have vastly improved my confidence in my own knowledge of
astronomy.As a result, I have found
myself constantly reconnected to what is fundamentally so exhilarating about
the subject.The
captured sense of wonder on a student’s face as they struggle with the
expansion of the universe or an imagined fall into a black hole is, in a sense,
why we astronomers are doing any of this in the first place.I have also had the opportunity in recent weeks
to discuss with my students both my supernova research and how it relates to my
recent article.It is especially
rewarding to see how students discover how to fit these concepts together,
grasping the connections between distant supernova explosions, the expansion
rate of the universe, the fundamental constants of physics, and the fact that
we humans exist to explore and question such a universe.This seems to me to be the essence of the
integration of research and education.

In regard to advancing diversity in
science, to be perfectly honest, teaching an introductory astronomy course does
not exactly qualify as community outreach.But it is certainly a taste of what impact I can make upon the lives of
individual students, in inspiring them to explore these ideas in the
future.And although I have had the
opportunity to teach students with diverse backgrounds, I can not claim credit
for their presence as students at UC Berkeley.The most I can say is that if I have in any way inspired an underrepresented
student to continue to pursue science, then I have done the best I could toward
advancing diversity.

In addition to my discussion sections, I
have also been doing volunteer tutoring at The Astronomy Learning Center,
(TALC), whose inception and continued existence is due largely to the efforts
of John Johnson, the head TA for Astronomy 10.In this setting, we encourage group and individual board work by
students in a relaxed and supportive intellectual environment.Independent of Astronomy 10, I have also done
group and individual tutoring in Physics and Astronomy as a volunteer at the
Student Learning Center (SLC) on campus.Many of the students who come to both TALC and the SLC happen to come
from underrepresented portions of the population.The fact that many of these students find
themselves in need of extra help is largely a reflection of sociological
conditions in the country as a whole.As
it is, in reality, these students are just as bright as any of their peers at
Berkeley, as evidenced in my experience, at TALC especially, by the significant
number of serious intellectual discussions I have engaged in with curious
students of all backgrounds.

For the most
part, as science professionals, we have the luxury of viewing our colleagues
simply as intellectual human beings, independent of our individual sociological
backgrounds.In this sense, the
scientific enterprise is perhaps unique in its wholeheartedly egalitarian and
merit based approach to advancing knowledge.In an ideal world, all groups would thus be equally represented in this
endeavor.As it is, women and minority
groups are still clearly underrepresented, and this problem must be
addressed.To this end, as a student and
teacher, I have always been willing to help all who are interested without
discrimination, and there is no doubt that I will carry that mindset for the
rest of my career.As a decent human
being, this is simply the least I can do.But purely as a scientist, I also want to explore and publicize the
types of questions that promote the most crucial kinds of intellectual growth
and discovery that science has to offer.In addition to publishing peer reviewed journal articles on my research
and engaging in popular science writing, I want to write textbooks, give public
talks, and lead seminars.Through
research, writing, teaching, and whatever other avenues present themselves, in
the end, I want make a lasting contribution to my community, and be a communicator of scientific ideas in as many ways as possible.

Proposed Plan of Research
Form

Applicant: Friedman, Andrew

In a clear, concise, and original statement, describe any research interests
you may pursue while on fellowship tenure. Your statement should demonstrate
your understanding of research principles necessary to pursue these interests
and explain the relationship to your previous research, if any. Present your
plan with a clear hypothesis or questions to be asked by the research. If you
have not yet formulated a plan of research, your statement should include a
description of one question that interests you and an analysis of how you think
the question may best be answered. A listing of courses alone is not
sufficient. Research topics discussed in your proposed plan may be used in
determining eligibility.Type single space using 10 point font size or larger. There
is a 2-page limit, including references.

As a graduate student in theoretical
astrophysics, I am primarily interested in critically examining the theoretical
foundations behind some of the major results of the observational research
group I have been involved with as an undergraduate at UC Berkeley.As described in more detail in my research
experience essay, since January of 1999, I have been working in astrophysics as
a member of the Lick Observatory Supernova Search group at UC Berkeley, headed
by Professor Alex Filippenko.Under the
auspices of the High Z supernova search team, we use observations of Type Ia supernovae to test various
cosmological models, and specifically, to measure the acceleration rate of the
universe.The recent supernova results
along with independent data gathered from cosmic microwave background (CMB)
measurements suggest that the expansion of the universe is accelerating.Initially, this result was the antithesis of
the decelerating universe that was expected.Indeed, it has been controversial enough throughout to force both my
group and another independent supernova group to become our own harshest critics,
and act quite cautiously in regard to taking the results on face value.As such, we have tested for several major
systematic errors, including chemical evolution of the Type Ia
progenitor systems, and reddening by interstellar dust, and found that our
results are largely unaffected.And now
that we have independent CMB data which is consistent with the supernova
results, the astronomical community largely accepts that the universe is
accelerating.The supernova results are
far from dogma, but they are beginning to be incorporated into the curriculum
of advanced astrophysics courses and newer textbooks, for example.As a theorist, in the cautious spirit of the
scientists I have been fortunate to learn from, I would like to critically ask
the question, “Is there any other effect
which could be mimicking what we interpret to be cosmological acceleration?”In other words, are these results physical,
or an artifact of an incorrect interpretation stemming from an incomplete
understanding of fundamental physics?Since I have not yet completely formulated a detailed research plan, in
this proposal, I will primarily discuss why this is an important and reasonable
question and broadly outline several potential avenues of theoretical research
along these lines that I hope to pursue in graduate school.

First of all, disregarding for a moment my
personal bias, it is not unreasonable to speak of the accelerating universe
results as one of the most important recent discoveries in all of physics, and,
quite possibly, all of science.It is
not inconceivable that, if the results hold up, the leaders of the relevant
projects could merit a shared Nobel Prize in physics within the next
decade.When a
scientific result this groundbreaking is released, an honest scientist thus has
to meet the idea with a reasonable amount of skepticism.We are in this field to answer fundamental
questions about the past, present, and future state of the universe as a whole,
and these cosmological questions are philosophically and scientifically
important enough that we owe it to ourselves and the scientific community to
subject any major results to sufficient peer reviewed criticism.And beyond that, it is not unreasonable to
say that we actually owe it to humanity to make a sincere effort at critical
examination.Granted, most United States
or World citizens might value esoteric astronomical discoveries, such as, say,
measuring the Neutrino mass, with comparatively low regard, but for a publicly
accessible result such as one that says, “The universe is roughly 14-15 billion
years old.” or, “The universe is accelerating in its expansion.”, a large
number of people are actually sincerely interested and affected.Regardless of the esoteric foundations of the
supernova results, the idea of the expanding and accelerating universe happens
to be quite conducive to the public imagination.It is within this big picture context that I
am motivated to investigate the validity of this result, aside from its pure
scientific interest.If the universe is
accelerating in its expansion, or if it is simply coasting along, these are
reasonable things for an educated human being to be aware of, just as it is
reasonable to understand that the universe likely began a finite time in the
past at the Big Bang.

But just as it is reasonable to continue
subjecting the Big Bang model to stricter and stricter tests, this result, as a
comparative toddler, should in no way be spared from a similar gauntlet of
critiques.First of all, there are
several motivations for the idea that, while the data analysis underlying the
supernova results may be robust, the assumptions that research groups have
adopted in interpreting the results may be in need of revision.The idea that the data analysis may be robust
comes from the fact that it is statistically unlikely that the independent data
analyses done by the High Z Team, the Supernova Cosmology Project, and the
MAXIMA, BOOMERanG, and DASI cosmic microwave
background collaborations are all intrinsically flawed, yet somehow still in
agreement.But if the shared theoretical
assumptions made by the all the groups are flawed at some level, the
interpretation of the results would be in question, even if we assume perfect
data analysis.The assumptions stem from
our current understanding of Einstein’s theory of General Relativity.

In the current interpretation, the
acceleration is caused by Einstein’s newly resurrected cosmological constant L,
which was originally an ad hoc repulsive gravitational term thrown in to
Einstein’s Field Equations in order to keep the universe static, as Einstein
believed it to be at the time.It now
serves as a repulsive gravitational force (cosmic antigravity) which causes the
expansion of the universe to accelerate.The idea of the cosmological constant being a real, physical quantity
has left a large number of scientists uneasy for several reasons.When we apply standard particle physics
theory, which treats the natural Planck energy density of the vacuum as the
physical basis for the cosmological constant, L, we get a number that is
10120 orders of magnitude larger than what we observe, quite
possibly the most numerically discrepant prediction in the history of
science!If the independent supernova
and CMB results are as robust as they seem, this clearly signifies that we are likely
to require significant change in our understanding of fundamental physics in
order to describe what, in fact, L actually is.As
it stands, our fundamental physics gives us an answer that is bordering on
ridiculous.

This alone naturally leads one to consider
that maybe we are being fooled somehow, observing an effect that looks like L and
cosmological acceleration, but is in fact, some other new physical phenomenon
altogether.Granted, this would defer
the problem of what L
is to some other source, but if the other source is more amenable to and
consistent with theoretical and observational tests, then as good scientists,
we can learn to live without L.This is not to deny the possibility that L is
real, (in fact, it is still our best bet thus far), but as honest scientists,
we must continue to be our own harshest critics and seriously consider the
possibility that General Relativity is flawed, and that the L we
think we are seeing is actually an artifact of some other yet to be understood
physical process.

It has been recently suggested by a group
at the University of New South Wales in Sydney, Australia, (Murphy, Webb et. al.) that observations of (Quasi-Stellar Object)
QSO absorption lines out to high redshift may indicate that the dimensionless
Hydrogen fine structure constant a may be changing in time.(Where a = e2/c = (electric charge) 2/ (Planck’s constant x the
speed of light) ).Some theorists, notably John D. Barrow, and Joao Magueijo,
have pointed out that this may mimic the behavior of L in a fashion that is
consistent with observations.As any
serious research team must do, the UNSW group is waiting for other independent
groups to confirm their results, and until then, one can not merely accept the
results without criticism.But the
theoretical motivations for a changing a, along with the robust
statistical tests employed by the UNSW group at the very least make this
observational result suggestive enough to prompt further theoretical
investigation, even before the result is either confirmed or constrained by
future independent observations.As one
of the possible explanations for what we interpret as L, a
theory that allows for varying a, and indeed any of the other physical constants, is an
avenue which may be legitimately explored.

A priori,
there are no reasons why the “constants” of physics should not be allowed to
change, so it is at least reasonable to investigate the explanatory power of
theories in which they can vary, and apply observational tests when
possible.Although a theory of changing
constants is not part of the current standard view, it is not a new idea in any
sense.Indeed, scientists as far back as
Eddington, Dirac, and
Wheeler gave serious consideration to space and time variation of the speed of
light and Newton’s Gravitational Constant, for example.Modern day theories such as string theory
that attempt to unify gravity with the other fundamental forces, naturally
contain extra compactified spatial dimensions whose scales determine the values
of the fundamental constants.Since we
have no a priori reason to expect that the scales of the extra dimensions will
remain constant as the expansion of the universe proceeds, variation in the
values of the constants is a natural prediction of such theories.Whether such unifying theories are worthwhile
is another question entirely, but suffice it to say that string theory and its
brethren are our current best attempts at a unified theory of quantum gravity,
and their preliminary theoretical findings are suggestive and compelling enough
to take very seriously.In addition to
the previously mentioned Barrow and Magueijo, Andreas
Albrecht, one of the founders of the modern theory of inflationary cosmology,
has seriously considered varying speed of light (VSL) models and how they would
impact our current understanding of cosmology.Albrecht has taken the stance that he is not investigating VSL models
because he is convinced they are correct, rather, he
is doing so to offset the fact that no serious modern opposing theory to
cosmological inflation has arisen.Rather than trying to sell a pet theory, Albrecht is simply trying to
keep science honest when it comes to our cosmological theories.It is in this spirit that I hope to analyze
the supernova results in graduate school.

Some would object to the idea of resorting
to a theory of changing constants to explain away L because it would seem to
decisively undermine the basis of fundamental physics as we know it.First of all, treating the “constants” as
constant will always be an excellent local approximation.Local classical physics thus remains
unharmed.It is only on the largest
cosmological scales and in our Standard Model of Particle physics where we will
require significant revision. As it stands, no one will deny that the standard
model of particle physics is incomplete.It has yet to incorporate gravity into its quantum mechanical framework
with electromagnetism and the strong and weak nuclear forces.Few will deny that our understanding of
gravity in, say, thirty years, is bound to be significantly different from our
current understanding.And we have
already concluded that if the independent supernovae and CMB results are not intrinsically
in error, and Lis real, we are already in the same situation.Fundamental physics must change in either
case.If we must choose between two
theories that may both be consistent with observations, one must consider which
theory possesses greater explanatory power.It may be that a changing fine structure constant, or some other
combination of changing constants can mimic the behavior of L, and
explain what is physically happening in a more logical and consistent
fashion.Or it may not.The point is that the question is of great
scientific interest, regardless of what the result may be.In other words, even if theories with
changing physical constants end up being terribly wrong, we can not help but
learn some interesting physics through their investigation.As a long-term theoretical goal, I would love
to help formulate a general theory of changing constants, to help provide a
framework within which further observational groups like the Lick Observatory
Supernova Search group, the High Z Team and the UNSW group can test whether the
constants do vary in space and time, and evaluate their impact on our
cosmological models.

Although,
as a theorist, I plan to become involved with more fundamental questions that I
can possibly predict at present, the idea that the cosmological constant could
be a mirage, possibly replaced by a new paradigm of fundamental physics where
the constants can vary, is a topic that highly interests me.Having been a researcher working in the
supernova field for several years now, as a potential theorist, I would
genuinely like to see the results through, whatever their eventual
interpretation may be.It is my hope
that, regardless of their eventual interpretation, the supernova results will
act as a springboard toward a new and better understanding of fundamental
physics, where yet again, astronomical observations cause us to radically
revise our understanding of nature.The
phenomenon is not unprecedented: Hoyle’s prediction of the resonant Triple
Alpha level required for the formation of Carbon 12, the solution to the Solar
Neutrino Problem, the Binary Pulsar and bending of starlight during a total
solar eclipse as a test of Einstein’s theory of General Relativity, to name a
few.The list is simply too large for
this page, and as a hopeful theorist, I would love nothing more than to help
add to it.In graduate school and
beyond, it is with this mindset that I hope to be a part of that tradition of
unbridled theoretical investigation.

References:(See Also the Research Experience References )

1.

Albrecht, A. Cosmology
with a time-varying speed of light. To appear in the proceedings of
COSMO98( astro-ph/9904185 14 Apr
1999)

Describe any scientific research activities in which you have participated,
such as experience in undergraduate research programs, or research experience
gained through summer or part time employment or in work-study programs, or
other research activities, either academic or job-related. Explain the purpose
of the research and your specific role in the research, including the extent to
which you worked independently and/or as part of a team. In your statement,
distinguish between undergraduate and graduate research experience. If you have
no direct research experience, describe any activities that you believe have
prepared you to undertake research. At the end of your statement, list any
publications and/or presentations made at national and/or regional professional
meetings.Type single
space using 10 point font size or larger. There is a 2-page limit,
including references.

Since January of 1999, I have been doing
research in Astrophysics as a member of the Lick Observatory Supernova Search
(L.O.S.S) team with Professor Alex Filippenko at the University of California,
Berkeley.We work under the larger
auspices of the High Z (i.e. high redshift) Supernova Search Team, headed by
Dr. Brian Schmidt at the Australian National University in Canberra.The big picture goal of the group is to
discover large numbers of Type Ia
supernovae in distant galaxies, determine their spectra and light curves from
follow up observations, and use them to do cosmology.My research has focused on both searching for
supernovae and performing photometry on the follow up observations to obtain
the supernova’s light curves, which plot its apparent brightness as a function
of time in several different filters (U,B,V,R and I bands).These light curves are then used to test various
cosmological models, and specifically, to measure the acceleration rate of the
universe.Since Edwin Hubble’s 1929
discovery that almost all galaxies are redshifted, and are thus receding from
us, we have known that the universe is expanding.The major result of the High Z Team, which
was announced first in 1998, is that the supernovae we observed are
consistently 10-15% dimmer than what we would expect from a coasting expanding
universe, implying that they were actually farther away than expected, and thus
that the expansion of the universe may actually be accelerating.

When I joined the group in early 1999, the
result was even more controversial than it is now because it flew in the face
of conventional wisdom that the universe was surely decelerating, as gravity
should eventually overcome the energy from the initial expansion. The results
also resurrected serious interest in Einstein’s Cosmological Constant
L, which in theory could
provide a cosmic antigravity force, which resists normal gravity and causes the
acceleration.As it happened, the
accelerating universe results were obtained independently through work done by
the Supernova Cosmology Project headed by Dr. Saul Perlmutter
at the Lawrence Berkeley National Laboratories.This gave both of our groups more confidence in a result that initially,
neither team was willing to believe, let alone publicize to the astronomical
community.Since then, crucial
independent tests of the possible cosmological models have been performed using
data from the Cosmic Microwave Background (CMB), most notably from the MAXIMA, BOOMERanG, and DASI experiments.These results are also consistent with the
supernovae results.Thus the present
consensus from the astronomical community is that we have an accelerating
universe with a nonzero cosmological constant, and an unwieldy list of
questions regarding the true physical basis for this phenomenon.

To use supernovae to answer cosmological
questions, we first look at a its spectra to determine
its redshift and see if we can classify it as a Type Ia.We use Type Ia
supernovae in particular because there is strong theoretical basis for the idea
that all Type Ia supernovae can be treated as
“standard candles”, in the sense that their intrinsic brightness does not vary
much amongst populations of Type Ia’s exploding over
cosmological timescales and thus at different redshifts.Assuming that Type Ia
supernovae are perfect standard candles, we can use them as relatively robust
cosmological distance indicators. Traditionally, we get a distance by measuring
the supernova’s apparent peak brightness from its observed light curve, and
comparing it with that of other Type Ia’s that
exploded in galaxies whose distance we have determined independently, for
example using Cepheid variable stars.Knowing both the distance and the intrinsic brightness of the supernova,
we can compare the apparent brightness we observe to the apparent brightness we
would expect to see from models with or without cosmological acceleration, and
test which model is most consistent with observations.

However, comparison between high and low
redshift supernovae in different environments is necessary to justify the
assumption that Type Ia supernovae can indeed be used
as reliable standard candles. Other effects, such as evolution of the chemical
composition of successive generations of these objects, or reddening by
interstellar dust could in theory change the intrinsic brightness of Type Ia supernovae as a function of
redshift.Testing this assumption and
providing the foundation for the understanding the high redshift supernovae is
a primary focus of the particular supernova search that I am involved in.We look for nearby, low redshift supernovae,
(Z < 0.1), whose spectra and light curves we determine and then compare and
combine with those of the high redshift supernovae found by the High Z
Team.By comparing both high and low
redshift supernovae, we can test for chemical evolution of the progenitor systems,
and extend our tests of cosmological models to regimes that require both high
and low redshift data points.

That said, if we
want to use these supernovae to do cosmology, the first thing one must do in
such a project is to find them!Our
team, which includes several undergraduates, searches for supernovae aided by
IRAF (Image Reduction and Analysis Facility) image processing software
specifically designed to find possible supernova candidates.Our data consists of CCD images that come
from the Katzman Automatic Imaging Telescope (KAIT)
located at Lick Observatory.The state
of the art program I work with, which was designed by my direct superior,
Assistant Research Astronomer Weidong Li, sifts
through images of as many as 1000 galaxies a night. However, the program itself is still not sensitive enough to
detect many supernovae, so it requires a careful observer to check through the
images and verify possible good candidates.In doing so, I use various IRAF programs to compare the current images
with template images of the same host galaxy taken previously to determine
whether there is indeed something new and re-observable in the CCD image, as
opposed to a fleeting asteroid or cosmic ray, for example.For promising candidates, I instruct KAIT
remotely to automatically re-observe the image to make sure that the apparent
supernova is still in the field of view, and can sometimes even get same day
verification.I am happy to say I have
been fortunate to discover seven supernovae in the past semesters.Pictures of the supernovae (1999bh, 1999bx,
1999ej, 1999gb, 200fa, 2001L, and 2001ae) can be found
on the KAIT website at http://astron.berkeley.edu/~bait/kait_lwd.html
under 1999, 2000, and 2001 discoveries.Once we make a discovery, it is announced with our name as discoverer,
via an IAU circular (International Astronomical Union) e-mail to a large
fraction of the astronomical community.

I took a six-month break from the group
during the Spring 2000 semester when I studied abroad
at the University of New South Wales in Sydney, Australia.Since returning, I’ve continued working with
the Filippenko group on a new research project in addition to the supernova
search, where I am learning how to perform photometry, the precise measurement
of the brightness of astronomical objects.I am in the process of working with Weidong
Li, our resident expert on KAIT and key technical member of our group, to learn
how to perform aperture and point-spread-function (PSF) fitting photometry on
individual supernovae.I start with a
data set of dozens of follow up CCD observations in different filters taken by
KAIT starting from the date of discovery and extending for several months to a
year.I then perform photometry on each
image in order to produce the supernova’s light curves in all the relevant
filters.I am currently working with
IRAF software packages, graphing scripts, occasionally Microsoft Excel, and
several programs written by Weidong Li with the long
term goal of producing light curves for as many as 30 Type Ia supernovae.I now spend most of my time in the group focusing on the photometry
project, while occasionally helping to train new undergraduates to do the
supernova search.

To begin the process, I did photometry on
a “practice” supernova (SN 2000cx), that occurred far from its host galaxy, and
compared my light curves with the data that Weidong
had already reduced, getting consistent results.That particular supernova has been discussed
in great detail in the recent paper by Weidong and
Alex, (Li & Filippenko 2001) listed in the references.I am now in the process of learning galaxy
subtraction, to deal with supernovae that occur closer to their host galaxy,
and currently working with Supernovae 1998dh.Galaxy subtraction is necessary because we want to isolate the light
coming from the supernova alone and remove contaminating light from the host
galaxy.If we have template images of
the galaxy taken before the supernova explosion, this process is
straightforward.In most cases, however,
we do not, which means we must wait a year or so until the supernova fades and
then take a calibration image of the host galaxy which we can then subtract
from our supernova images.During the
rest of this semester, and in the Spring before I attend graduate school, I
plan to continue working with the group and apply the techniques of galaxy
subtraction and PSF photometry to generate the light curves for supernova
1998dh and a number of the 30 or so Type Ia
supernovae who we have followed extensively with KAIT.Most of them have data that are simply
waiting idly while we try to get good calibration images of the host galaxy,
without which we can't even begin to do any of the galaxy subtraction or
photometry.I also plan to help train
the new undergraduates in the group, so we can efficiently approach the task of
reducing the considerable about of supernova data we have.

In the end, the completed analysis and
light curves, along with a training primer discussing how to do KAIT photometry, should form the bulk of my senior honors thesis
research.When we eventually publish
these light curves, I will end up as second or third author on a paper along
with Weidong and Alex, where we present the addition
of the new data to our sample.The work
is of considerable interest to astrophysics, especially to those in the
supernova field, as we would effectively be extending the current useful
database of nearby supernovae by roughly 30%.In addition, our light curves are better sampled than those previously
published (i.e. more follow up images, closely spaced in time), and would
likely become the new “training set”, with which to compare all subsequent Type
Ia supernovae light curves, providing even stricter
tests of the accelerating universe results.All in all, I feel like I am making a positive contribution to the
group, learning a tremendous amount, and definitely preparing me for possible
Astrophysics research in graduate school, although right now I am leaning
significantly towards astrophysics theory rather than observational astronomy,
due mostly to the huge number of tantalizing unsolved problems I have been
introduced to in the context of both my academic and research experiences here at
Berkeley.

This semester, I have also been involved
in the perpetual motion experience that is the UC Berkeley Undergraduate
Infrared Astronomy Laboratory taught by Professor James Graham.The amount I have learned in a mere 10 weeks
has been exponential at the very least.In order to write up my labs, I have had to develop a competent
familiarity with the Unix operating system, become
proficient programming in IDL (Interactive Data Language), and learn to use the
LaTeX document formatting language, in addition to
the conceptual core material of the lab.The learning curve is pretty steep, and in a very short time we all
become pseudo experts.There are very
few courses that can boast such things.So far, in addition to Unix, IDL programming, and
LaTeX, I have learned a tremendous amount regarding
statistics, error analysis, CCD pixel array imaging, and how to take images of
stars with a robotic telescope, (The Leuschner
Observatory 30-inch telescope and Infared
Camera).These are some of the fundamental
tools of a modern day astronomer.

The lab material has also been integrally
related to my supernova research.My
last lab report, “Photometric observations with the Leuschner
Telescope and Infrared Camera”, considerably solidified my understanding of the
photometry I have done for supernovae.Instead of simply using part of the massive IRAF software package
infrastructure, or programs written by Weidong Li,
this time I wrote the software to perform differential aperture photometry on individual
stars from the ground up.Even though
using the programs clearly requires an understanding of the underlying
theoretical motivations and major workings of the program, it is no substitute
for writing the program yourself.I have
already applied what I have learned in this laboratory toward teaching some of
the new undergraduates in my research group about differential photometry,
hopefully providing them with a big picture view of what we are doing and why
we are doing it in the first place.On a
broader level, the programming skills I acquire in this lab will be generally
applicable to whatever topics I pursue as a theoretical astrophysicist.But perhaps most importantly, through this
lab, I am learning more about what it takes to write a concise, clear, and
honest scientific paper, and to present my results to a community of my
peers.

Last April, as part of my
honors thesis, I spoke at the Berkeley Undergraduate Research Poster
presentation organized by theSociety of Physics Students,
discussing the accelerating universe results and my role in the supernova
search.

Graham, James, and Treffers, R.R. An
Infrared Camera for Leuschner Observatory and the
Berkeley Undergraduate Astronomy Lab, Publications of the Astronomical
Society of the Pacific, 113, pg. 607-621, May 2001.